Optically-active D-.alpha.-amino acids are important compounds as intermediates of drugs, and particularly, D-phenylglycine, D-parahydroxyphenyl-glycine and other intermediates for the production of semisynthesized penicillin or cephalosporin antibiotics are industrially useful compounds. As a process for the production of such D-.alpha.-amino acids, there is a well-known process in which carbamoyl groups of the corresponding D-N-carbamoyl-.alpha.-amino acids are removed to give the desired D-.alpha.-amino acids. The removal of carbamoyl groups in this process is achieved by a chemical process (e.g., the specification of Japanese Patent Publication No. 58-4707) or by a process utilizing the enzymatic reaction of microorganisms (e.g., the specifications of Japanese Patent Publication Nos. 57-18793, 63-20520, and 1-48758).